'mount -p' can return multiple mount points. Use the first one.

Bug #158920 r=sspitzer

build/cygwin-wrapper

@@ -7,7 +7,7 @@ shift
 if test -z "$prog"; then
     exit 0
 fi
-mountpoint=`mount -p | grep ^/ | awk '{ print $1 }'`
+mountpoint=`mount -p | awk '{ if (/^\//) print $1 }' | head -1`
 if test -z "$mountpoint"; then
    print "Cannot determine cygwin mount points. Exiting"
    exit 1

config/make-jars.pl

@@ -4,7 +4,7 @@
 
 my $cygwin_mountprefix = "";
 if ($^O eq "cygwin") {
-$cygwin_mountprefix = `mount -p | grep ^/ | awk '{print $1}'`;
+$cygwin_mountprefix = `mount -p | awk '{ if (/^\//) print $1}' | head -1`;
 } else {
 # we'll be pulling in some stuff from the script directory
 require FindBin;